At present, electrochemical reduction of CO₂ is favored at cathode under highly alkaline conditions while O₂ is produced via oxygen evolution reaction (OER) at anode. Unfortunately, carbonate is formed under these conditions, consuming both OH^– and CO₂ thus lowering the local pH and carbon efficiency. Anion exchange membrane, separating cathode and anode of the electrolyzer, enables a high local pH at cathode and mitigates CO₂ loss simultaneously. Still, a significant amount of CO₂ reacts with OH^– to form carbonate at cathode which crosses the anion exchange membrane to the anode. As a result, CO₂ is released together with O₂ produced at anode, producing a gas mixture of CO₂ and O₂. The separation of CO₂ from O₂ is needed to improve the carbon efficiency, but the energy penalty is prohibitive at this moment. Recently, Sargent et al report a liquid-to-liquid anodic process that enables the recovery of crossovered CO₂ without additional energy input (doi.org/10.1038/s41467-022-30677-x).  In this report, an all-liquid anodic process was adopted. CO₂ reduction reaction was coupled with glucose oxidation reaction (GOR) instead of OER, offering a low full-cell voltage of 1.9V. CO₂ was recovered from anode via facile gas/liquid separation and fed to cathode with fresh CO₂, achieving a total carbon efficiency of 48%, and a 46% reduction in energy intensity compared to the state-of-art single stage CO₂ to C₂₊ devices. The strategy is compatible with today’s highest-efficiency electrolyzers and CO₂ catalysts that function optimally in neutral and alkaline electrolytes.

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